Bookkeeping Google Sheet Template for Efficient Tracking

System Design: Building a Bulletproof Payment Gateway! 🚀 Basic payment setups fail during network timeouts. To block catastrophic duplicate charges, enforce client-generated idempotency keys (UUIDs). The server saves this key first; if a duplicate request arrives, it immediately returns the cached result instead of re-charging the buyer. Never overwrite database rows to update payment statuses. Instead, implement an immutable ledger where every state change—authorized, captured, or refunded—cre

The Country That Was in the Axis for Only Two Days #history #didyouknow #ww2